Abstract

Established human mammary tumor cell lines constitute an important tool in the study of breast cancer. The aim of this work was to isolate and characterize two new mammary tumor cell lines, JCK and GCS, which were obtained from the pleural effusion and ascitic fluid, respectively, from two breast cancer patients. Both cell lines had some properties of transformed cells, namely immortalization and growth in soft agar. The carcinoma cells presented epithelial morphology shown by light and electron microscopy, and antigenic properties shown by different tumor markers such as a cytokeratin cocktail, carcino-embryonic antigen, epithelial membrane antigen, and human milk fat globule membrane antigen. A significant increase was also found (P > 0.05) in cell growth and H-3-thymidine incorporation into DNA in the JCK and GCS cell lines in the presence of 17-beta-estradiol at concentrations of 10(-9) and 10(-7) M, respectively, after 5 days in culture. These cells presented estradiol receptor levels which were similar in the biopsies and the resulting cell lines. The aromatase activity was also similar in the JCK cell line and the original patient biopsy. However, there was a considerably higher aromatase activity in the GCS cell line than in the biopsy specimen. Southern hybridizations with the neu oncogene showed an additional 12 kb fragment in both cell lines, as also seen in patients with breast cancer. We conclude from these studies that this in vitro system may provide us with a way to study metastatic cells and improve clinical management of breast cancer patients.